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Wind loads of building structures
Štěrba, Martin ; Kala, Jiří (referee) ; Hradil, Petr (advisor)
The bachelor thesis deals with the analysis of the effects of wind load on building structures. In the context of the work is solved the numerical modeling of flow around the solid cylindrical bodies at high Reynolds numbers. To the simulations has been used computational software ANSYS CFX. The outputs of the work are the values of Strouhal numbers and the values of drag and lift coefficient depending on the Reynolds number.
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Implementation of wall functions into a hybrid fictitious domain-immersed boundary method
Kubíčková, Lucie ; Isoz, Martin
Hybrid fictitious domain-immersed boundary method (HFDIB) is a simulation approach used in computational fluid dynamics. The approach avoids usage of complex geometry-conforming computational domains. Instead, a simple domain is used and the geometry is projected onto it by a scalar field and adjustment of governing equations. Hence, the time spent on mesh generation is substantially reduced. It is advantageous to use the HFDIB in geometry optimizations where it allows for a massive optimization speed-up. Nevertheless, there is a problem with simulation of the fluid behavior in the boundary layer in the vicinity of the immersed walls. Especially, in simulation of highly turbulent flows, where the boundary layer is very thin and the usage of finer mesh is unaffordable. In this work, we aim to solve this problem by implementation of Reynolds averaged turbulence models in our custom HFDIB variant. In particular, we implemented the k-ω turbulence model and blended wall functions for closure variables and velocity.
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On Reynolds-averaged turbulence modeling with immersed boundary method
Kubíčková, Lucie ; Isoz, Martin
The immersed boundary (IB) method is an approach in the computational fluid dynamics in which complex geometry conforming meshes are replaced by simple ones and the true simulated geometry is projected onto the simple mesh by a scalar field and adjustment of governing equations. Such an approach is particularly advantageous in topology optimizations (TO) where it allows for substantial speed-up since a single mesh can be used for all the tested topologies. In our previous work, we linked our custom IB variant, the hybrid fictitious domain-immersed boundary method (HFDIB), with a TO framework and successfully carried out an optimization under laminar flow conditions. However, to allow for optimizations of reallife components, the IB approach needs to be coupled with an affordable turbulence modeling. In this contribution, we focus on extending the HFDIB approach by the possibility to perform Reynolds-averaged simulations (RAS). In particular, we implemented the k − ω turbulence model and wall functions for closure variables and velocity.
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Influence Boundary Layer In The Differentially Pumped Chamber
Bílek, Michal ; Hlavatá, Pavla
The goal of this thesis is the analysis of a gas flowing through the drain channels within the apertures of differentially pumped chamber of the Environmental Scanning Electron Microscope (ESEM). This thesis contains a verification of current simulation results of gas flow within the differentially pumped chamber published by D. Danilatos using Monte Carlo method in comparison with simulation results achieved by using simulation program ANSYS Fluent, which uses the mechanism of continuum for its calculations and where it was effect of the boundary layer taken into account.
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Wind loads of building structures
Štěrba, Martin ; Kala, Jiří (referee) ; Hradil, Petr (advisor)
The bachelor thesis deals with the analysis of the effects of wind load on building structures. In the context of the work is solved the numerical modeling of flow around the solid cylindrical bodies at high Reynolds numbers. To the simulations has been used computational software ANSYS CFX. The outputs of the work are the values of Strouhal numbers and the values of drag and lift coefficient depending on the Reynolds number.
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